A comparison of histocompatibility antigens in dermatitis herpetiformis and adult coeliac disease.

The incidence of histocompatibility antigens HL-A, 4a and 4b was studied in thirty-eight patients with dermatitis herpetiformis (DH) and thirty-six patients with adult coeliac disease (ACD). The 4b antigen was found in all the DH and ACD patients. HL-A 8 was found in 89% of patients with ACD--similar to the incidence reported in previous studies--and in 79% of patients with DH, a higher incidence than in previous studies which may be due to stricter criteria being used here to diagnose DH. There was no significant difference in the incidence of HL-A 8 between those patients with DH whose small intestinal biopsies appeared macroscopically abnormal and those with a normal macroscopic appearance. These findings suggest that patients with DH form a single disease group and do not support the concept previously postulated that there are two groups of patients with DH, one with an increased incidence of HL-A 8 antigen similar to that in ACD who have a gluten sensitive enteropathy (GSE), and another with a normal incidence of HL-A 8 antigen and without enteropathy.